Obesity associated cancer is an important health issue. Major risk factors of obesity leading to cancer, through multiple signaling pathways, are insulin, insulin like growth factors, adipokines, and cytokines which are released from adipose tissue. The important signaling pathways are phosphoinositide 3-kinase (PI3K/ Akt), mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3). The PI3K/Akt and MAPK pathways have downstream effect on mammalian target of rapamycin (mTOR) leading to obesity associated cancer. Recent studies mostly focus on inhibition of mTOR for cancer therapy. It is essential to focus on PI3K/Akt, MAPK and STAT3 pathways which are under the impact of many cancer risk factors in obesity. Thus, signaling pathways may provide a novel approach for obesity associated cancer risk. In this review the signaling pathways linking obesity associated cancer are summarized.